Casting dental plates.



140. 700,855. Patented May 27, 1902'. W. STREETMAN. CASTING DENTAL PLATES.

(Application filed June 13, 1901.)

(N0 Modal.)

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UNITED STATES WILLARD STREETMAN,

PATENT OFFICE.

OF OLEBURNE, TEXAS.

CASTlNG DENTAL PLATES.

SPECIFICATION forming part of Letters Patent No. 700,855, dated May 27, 1902.

Application filed June 13,1901.

To all whom it may concern.- I

Be it known that I, WILLARD STREETMAN, residing at Cleburne, in the county of Johnson and State of Texas, have invented certain new and useful Improvements in Casting Dental Plates; and I do declare the fol lowing to be a full, clear, and exact descrip-. tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the let ters of reference marked thereon, which form a part of this specification.

This invention relates to metal-casting, and has especial reference to casting aluminium for dental plates. Heretofore in casting dental plates of aluminium it has been found impossible, owing to the very light specific gravity of that metal, to completely expel the air from the mold as the metal is poured in, on which account innumerable bubbles or pinholes appear in the casting, rendering it unfit for use as a dental plate. Former processes and existing apparatus have also failed to prevent shrinkage of the plate in cooling and have also proved to be inadequate to secure sharp and well-defined outlines and details, as formed in the matrix.

This invention overcomes all these and other defects in aluminium-casting and is a progressive development of the art partially or imperfectly illustrated in a patent granted to me September 19, 1899, No. 633,222.

The invention includes in its exterior structure a flask and neck made separately from each other and each in two separable members. The neck is nearly or quite as large as the flask in horizontal measurement, and means are provided for holding all the parts in operative position. Additionally and of greater importance the invention includes a channel flaring at the mouth or entrance of the neck, quite large in both its major and minordiameters,and taperinggradually down through the neck and through the investment in the flask to the upper edge of the matrix.

The accompanying drawings illustrate the invention, in which- Figure 1 is a side elevation, and Fig. 2 is an elevation showing the interior of one side of the device. Fig. 3 is an edge elevation, and Fig. & is a vertical section of Fig.

Serial No. 64,431. (No model.)

Like lettersof reference denote corresponding parts in the several views.

The letters A A indicate the two members of. the flask and B B the two members of the neck.

a and a] are eyes and bolts on the flask to bind its two members together, and b b are eyes and bolts on the neck to bind its two members together.

at? a are vertical nibs on the flask which engage recesses Z1 b in the neck and prevent lateral movement of the neck on the flask. The device is supported by the spreading legs a a O is the investment of refractory material, in which the matrix is formed by a model in the usual manner. The neck may be lined with this material, or it may be made of plumbago or other suitable material and be used without a lining, as shown in the drawings. The top of the flask and the bottom of the neck at their places of contact are plane'and smooth, except for the means employed to keep them in their proper relative position.

D is the flaring entrance to the neck.

E is the tapering channel through the neck, and E the continuation of said channel into the investment in the flask to the upper edge or" the matrix. In a dental plate the upper edge of the upper plate is horizontal or across the matrix; but for a lower plate the upper edge curves with the formation of the jaw or gum,and its upper edge in the flask curves downward accordingly. Therefore when casting a lower plate the investment must be cut away to form the tapering channel down to this edge of the matrix.

The channel E in the neck is permanent when the neck is not lined; but in the flask the channel E is cut away for each casting, and the two channelsE E must of course be in alinement. The channel should taper in both its major and minor diameters.

WVhen the mold is ready for casting and the investment perfectly dry, the neck is heated very hot and set upon the flask, which should be cold. The aluminium should be brought to a very high temperature and be poured into the mouth of the channel at one edge of the neck (marked D in Fig. 2 of the drawings) until the matrix and channel are filled to the top. It will then be found that -IOO after cooling the plate is perfectly cast and that all the shrinkage appears in the neck and usually only at the top.

It is obvious that the means and method herein described may be effectively applied in casting any metal and for other purposes than for dental plates, and my claim is for casting any kind of metal for any purpose whatever.

Having now described my invention and the manner of using it, what I claim, and desire to secure, is-

1. In a mold for casting metals, a flask provided with a neck and containing an investment the neck approximately as large as the flask, in horizontal measurement, and a pouring-channel in the neck flaring at the top and tapering thence in both diameters through the neck and into the investment in the flask to the upper edge of the matrix.

2. In a mold for casting metals, a flask provided with a neck and containing an investment, and a wide pouring-channel tapering in both of its diameters, through the neck and into the investment in the flask, to the upper edge of the matrix as herein set forth.

3. A device for casting metals consisting in a flask with a plane top made in two mem-- bers means for binding said members together, Vertical nibs at the top of each memin the investment in said flask, substantially as herein set forth.

In testimony whereof I affix my signature in presence of two witnesses.

WILLARD STREETMAN. \Vitnesses:

J. T. JoPLIN, R. B. VIoKERs. 

